Method for processing black and white photographic silver halidematerial

ABSTRACT

A method for processing black-and-white negative photographic silver halide materials which comprises (a) developing the exposed black-and-wite photographic material, (b) bleaching said photographic material without oxidizing and dissolving the silver in a bleaching solution, and (c) subsequently developing said photographic material again with a black-and-white developer.

United States Patent Sugiyama et al.

Oct. 2, 1973 METHOD FOR PROCESSING BLACK-AND WHITE PHOTOGRAPHIC SILVERHALIDEMATERIAL Inventors: Mitsunori Sugiyama; Shoji Ishiguro;

Nobuo Sugiyama; Haruhiko lwano; Yoo Iijima, all of Kanagawa, JapanAssignee: Fuji Photo Film Co., Ltd.,

Kanagawa, Japan Filed: Mar. 16, 1971 Appl. No.: 124,942

Foreign Application Priority Data Mar. l6, 1970 Japan 45/22l78 US. Cl96/63, 96/48 QP, 96/50 R, 96/61 R, 96/61 M, 96/66 R Int. Cl. G03c 5/24,G030 5/30, G03c 5/26 Field of Search 96/63, 66, 61, 50, 96/48 OF [56]References Cited UNITED STATES PATENTS 1,814,788 7/1931 Tartas 96/592,178,896 11 1939 Pifer 96/59 3,l78,282 4/1965 Luckcy et al. .1 96/64Primary Examiner-Norman G. Torchin Assistant Examiner-M. E. KelleyAt10rneySughrue, Rothwell, Mion, Zinn & Macpeak 57 ABSTRACT 14 Claims,No Drawings METHOD FOR PROCESSING BLACK-AND WHITE PHOTOGRAPHIC SILVERHALIDEMATERIAL BACKGROUND OF THE INVENTION 1. Field of the InventionThis invention relates to a method of treating blackand-white negativephotographic silver halide materi als, and more particularly, it isconcerned with a novel developing method which contains both a bleachingstep and a second developing step between usual development process.

2. Description of Prior Art In general, treatment of black-and-whitenegative photographic materials is carried out in the order of( ldevelopment, (2) stopping, (3) fixing and (4) washing. Somelight-sensitive materials, such as lithographic film, X-ray film,facsimile film (telephotographic film) and photographic plates formaking an integral circuit require a high contrast and sufficientmaximum density. For these purposes, various additives or developershaving a special composition are used.

However, these treatment methods have not been satisfactory because theyare also accompanied by some disadvantages, as mentioned hereinafter.

The disadvantages will now be illustrated, for example, with respect toa lithographic film. For the preparation of a screened dot image, a highcontrast silver halide material generally called lith film" is used. Theoriginal with continuous gradation is divided into a group of dotsarranged in a network. That is to say, the density change is convertedinto an area change of dots and recorded on the lith film. Division intoa dot group of a network is carried out by the use of a glass crossscreen or contact screen. An image of the original is printed throughsuch screen on a lith film or plate and then subjected to development,thus obtaining a dotted image. It is most preferable that such dot imageconsist of image spots having a maximum density andbackground having aminimum density, but formation of intermediate density zones calledfringe" around the dots is unavoidable since even a high contrastphotographic light-sensitive material has an intermediate density orso-called half tone portion. The fringe tends to degrade the quality ofa printed image-and, accordingly, is not preferred in plate making. Theless the fringe is, the better the quality of the dot image. Developmentof a lith film or lith plate is ordinarily carried out with an alkalinedeveloper containing hydroquinone as a developing agent and analdehyde-alkali metal bisulfite adduct, ascorbic acid and anacetonebisulfite adduct as a preservative. In this developer, theconcentration of free sulfite ion is low and thus the oxidizedhydroquinone is not activated through formation ofhydroquinonemonosulfonic acid. Rather a com pound more active thanhydroquinone is formed, thus causing a rapid and strong development.Even if this so-called lith development is carried out, completeelimination of the fringe around the dot is impossible.

SUMMARY OF THE INVENTION It is therefore an object of the presentinvention to provide a method for treating a black-and-white negativephotographic material for forming a high contrast silver image.

It is another object of the present invention to provide a method fortreating a black-and-white negative photographic material for obtaininga high developed density.

It is a further object of the present invention to provide a newtreatment method for obtaining a dotted image, having an excellent dotquality, whereby fringes around dots are effectively removed.

These objects can be accomplished by developing an exposedblack-and-white negative photographic silver halide material, and thensubjecting it to a mild bleaching treatment and a second development.

The following embodiments are given in order to illustrate the inventionin detail without limiting it:

Method I l. lith development 2. stopping 3. bleaching 4. rinse 5. seconddevelopment 6. stopping 7. fixing 8. water washing Method II lithdevelopment bleaching rinse second development stopping fixing waterwashing Method III lith development bleaching rinse mono bothdevelopment and fixing water washing Method IV same as Method III exceptrinse step is omitted As is evident from the above-mentionedembodiments, a method of treating blaclr and-white negative photographicmaterials according to this invention is characterized by the steps ofbleaching and second development after the ordinary development.

DETAILED DESCRIPTION OF THE INVENTION Methods II to IV are those whichare more simplified than Method I. Their steps will now be illustrated,and in particular, with respect to a lith sensitive material. The lithdevelopment as the first step is similar to the ordinary lithdevelopment (so-called infectious developer), i.e., using a lithdeveloper containing a developing agent, such as hydroquinone, apreservative such as a sodium bisulfite-paraformaldehyde adduct,ascorbic acid or kojic acid, an alkaline agent, such as sodium carbonateor caustic soda, and a fog inhibitor, such as potassium bromide orl-phenyl-5-mercaptotetrazole. For example, Developer Super Lithodol(trademark, manufactured by Fuji Photo Film Co.) is a lith developersuitable for application in this invention.

When using a 1.5 percent aqueous solution of glacial acetic acid as astopping bath, the lith development can be completely stopped for 10seconds. As in Method II, the bleaching bath may hold another action asastopping bath.

The bleaching bath contains an oxidizing agent and a halide compound,and if necessary, may contain an acid or an alkali as a pH regulator,another salt having a buffering action and a further salt to raise theionic strength.

As the oxidizing agent, there are used potassium or sodium bichromate,ferricyanide and sodium or ammonium persulfate, and as the halidecompound, there are used sodium, potassium and ammonium chloride,bromide and iodide. In addition, an acid, such as acetic acid,hydrochloric acid or nitric acid, and a salt, such as sodium acetate orsodium hydrogen phosphate may be added. Bleaching time, depending uponthe variety of a light-sensitive material as well as the composition ofthe bath, may range from 5 to 100 seconds, preferably to 30 seconds. Inthis case, the bleaching solution must have a pH of no less than I toprevent the dissolution of silver.

The step of rinsing after the bleaching step may ordinarily be carriedout by immersing in water for several seconds to 1 minute. Flowing watermay be used or the rinsing step may be omitted as in usual IV withoutany substantial effects. 1-2 percent aqueous solutions of sodium sulfitemay be used as a rinse solution. In any case, a suitable procedure maybe taken as the occasion demands since this step serves to prevent thesecond developer from contamination of the bleaching solution so as tolengthen the effective life thereof.

The step of second development following the rinse step is not alwayscarried out by the lith development, but the commonly usedblack-and-white developer may also be used. For example, commercialdevelopers, such as Super Lithodol and other developers such as D-76,D-72, D-8, FD-3, FD-3l, D-85, FD-l85, PM-MK and D-l9 mentioned in"Kaguku Shashin Benran" II Ed., pages 58-67 (published by Maruzen Co.)may be used. In these developers there may be incorporated one or moredeveloping agents,, such as metol(pmethylaminophenol sulfate),hydroquinone, l-phenyl- 3-pyrazolidone, 2,4-diaminophenol hydrochlorideand N,N-diethyl-p-phenylenediamine, one or more of alkaline agents, suchas sodium carbonate, caustic soda, trisodium phosphate, borax andpotassium metaborate, one or more preservatives, such as sodium sulfite,ascorbic acid and hydroxylamine and other developing aids.

The second developer may be a mono-bath developing and fixing solutionas mentioned in Method III. In this case, the subsequent processings aremarkedly simplified. The one-bath developing and fixing solution may beprepared by adding to the above-mentioned black-and-white developer oneor more silver halide dissolving agents, such as sodium thiosulfate,potassium thiocyanate, ammonium thiosulfate, sodium thiocyanate andthioglycollic acid and adjusting suitably the pH and concentrations ofthe chemicals. The basic consideration of the composition thereof isdisclosed by A. A. Newman in the British Journal of Photography 106,4448, 56, 66-68 (1959). The period of time for the second development isabout 10 to 200 seconds, preferably 30-80 seconds in respect of theworkability.

Following the second development, processings by the ordinary stoppingbath and fixing bath are carried out in the case of Methods l and II,but the stopping bath may be omitted without any substantial effects.

The method of this invention is apparently similar to the method oftreating a black-and-white reversal film, but in practice they areessentially different. In the case of the black-and-white reversal film,the steps of bleaching and second development are also carried outfollowing the developing step. In this case, however, I

the bleaching solution used is a sulfuric and acetic acid acidicsolution of potassium bichromate (pH: less than l) which is muchstronger than the bleaching solution of this invention and capable ofoxidizing and dissolving the developed silver completely. The bleachingsolution of this invention holds the developed silver forming a dotimage as it is in the film. In the treatment of a reversal film, afterthe bleaching step, it is radiated by white light to form a latent imageon an unexposed area, while in the method of the present invention, theradiation of white light is not carried out and, therefore, theunexposed area is not developed even in the second development; only thedot area is developed. This is a negative development.

The quality of a dot image according to this invention is improved somuch that a sharp printing image may be given. In addition, the dotimage correction operation called dot etching," which is often carriedout after development to improve the dot quality of screened negatives,is not required according to the method of the invention.

Another advantage of this invention is that it is possible to makethinner the thickness of an emulsion on a lith film or lith plate, thussaving the emulsion. The lith film or lith plate has an emulsion layercontaining a relatively large amount of silver halide in order to raisesufficiently the blackened density of a dot image and to make the fringeas little as possible. Therefore, it is relatively expensive. The methodof the invention can give such an excellent dot image quality thatsaving of silver halide is possible by thinning the emulsion layer or bydecreasing the content of silver halide in the emulsion layer.

The method of this invention is applicable to treatment of any lith filmor lith plate. It is applicable to any of silver chloride, silverbromide, silver chlorobromide and silver chloroiodobromide. Furthermore,it may be used irrespective of color sensitization, chemicalsensitization and addition of a sensitizer, such as polyethylene glycol,or fog inhibitor, such as tetrazaindene and other additives.

The foregoing illustration is based on only a dot image photographicmaterial, but the method of the invention is applicable to processing ofX-ray photographic materials, facsimile films and photographic platesfor making an integrated circuit, and other black-and-white negativephotographic materials. The resulting image is hardened and highlydensed. Of course, development may be carried out with an ordinarydeveloper.

A better understanding of the present invention will be obtained fromthe following examples which are merely illustrative of the presentinvention and not limitative of such.

EXAMPLE 1 A commercial lith film was subjected to stepwise dot imageexposure through a magenta contact screen of I33 lines and step wedgefor sensitometry and then subjected to the following two developmentsfor comparison:

Standard treatment (prior art method) developer I 20 C 3 minutesstopping 20 C 15 seconds fixing 20 C 3 minutes water washing 20 C 5minutes Improved treatment (A) developer l 20 C 3 minutes stopping 20 C15 seconds bleaching solution I 20 C 15 seconds rinse 20 C 30 secondssecond development'l 20 C 60 seconds stopping 20 C 15 seconds fixing 20C 3 minutes water washing 20 C 5 minutes The compositions of thetreating solutions are as follows:

Developer I water 500 ml sodium sulfitc 30 g paraformaldehyde 7.5 gpotassium hydrogen sulfite 2.6 g horic acid 7.5 g hydroquinone 22.5 gpotassium bromide 1.6 g

water to I000 ml Stopping solution 1.5% aqueous solution of glacialacetic acid Fixing solution sodium thiosulfate 200 g sodium sulfate 15 gsodium acetate I g glacial acetic acid 20 ml phassium alum I g water toI000 ml Bleaching solution potassium bichromate 20 g 3% aqueoushydrochloric acid 50 ml water to I000 ml Second developer I same asDeveloper I The dot image samples treated by the abovementioned twomethods were traced by a microdensitometer to measure the extension offringe around dots.

The results are shown in Table I, from which it is evident that theextension of fringe in the method of this invention is less than in thestandard method. In this table, Dot Area Ratio means a ratio of theblackened parts of dots to a sample area and Extension of Fringe means avalue of the size of a dot at a trace image density of 0.3 (diameter)minus the size at a density of 2.5.

A commercial lith film was exposed in a similar manner to that ofExample I and then subjected to the following treatment:

Standard treatment same as Example I Improved treatment B Bleachingsolution II in place of Bleaching solution I of Improved treatment ABleaching solution II potassium bichromatc 20 g sodium chloride 30 gglacial acetic acid 30 ml water to I000 ml Improved treatment CBleaching time is lengthened to 30 seconds in Improved treatment BImproved treatment D Bleaching solution III is used in place ofBleaching solution I in Improved treatment A Bleaching Solution IIIferricyanide potassium bromide water to I000 ml Improved treatment EBleaching solution IV is used in place of Bleaching solution I ofImproved treatment A Bleaching solution IV ferricyanide sodium chloridewater to I000 ml Improved treatment F Bleaching time is lengthened to 30seconds in Improved treatment E Improved treatment G Bleaching solutionV is used in place of Bleaching solution I in Improved treatment ABleaching solution V ferricyanide 35 g sodium chloride 60 g glacialacetic acid 60 ml water to I000 ml The results are shown in Table 2,.from which it is evident that the extension of fringe in the method ofthis invention is markedly reduced as compared with the prior artmethod.

TABLE 2 Treatment Method Extension of fringe at a dot area ratio of 50%Standard (prior art) 30;;

Improved treatment:

O-nrnUOw EXAMPLE 3 A commercial lith film was exposed in a similarmanner to that of Example 1 and then subjected to the followingtreatments:

Improved treatment II Developer I 20' C 3 minutes Stopping 20 C I5seconds Bleaching solution VI 20 C 30 seconds Rinse 20 C 30 secondsSecond developer II 20 C seconds Water washing 20 C 5 minutes Thecompositions of the treating solutions are as follows:

Bleaching solution VI potassium bichromate 20 g 3% aqueous solution ofhydrochloric acid I50 ml water to I000 ml Second developer II Thefollowing compounds are added per 1000 ml of Developer I: addition saltof formaldehyde.

and sodium sult'lte 35 g caustic soda 5 g I-phenyl-5-mercaptotetrazol0.I g methanol I0 rnl potassium thiocyanate I00 g Improved treatment Isame as Improved treatment I-I except using Bleaching solution V inplace of Bleaching solution VI in Improved treatment H Improvedtreatment .I

Second developer in Improved treatment H is substituted by the followingSecond developer III Second Developer Ill Potassium thiocyanate ofSecond developer II is converted into 70 g/l of sodium thiosulfate As isevident from the results shown in Table 3, the effects of the inventioncan be attained even if the processings after the second development aresimplified by a one-bath developing and fixing solution.

TABLE 3 Treatment Conditions Extension of fringe at an area ratio of 50%Standard treatment 30;]. Improved treatment: H 7y.

I lOp.

EXAMPLE 4 A support member was coated with each of silver chloride,silver bromide and silver chlorobromide (silver chloride 70 mol percent)to prepare a photographic film, which was then subjected to dot imagephotographing in a similar manner to that of Example I and Standardtreatment of the prior art and Improved treatment K.

Improved treatment K are added per 1000 ml of Developer II Extension ofthe fringe of dot was reduced by the method of the invention as shown inTable 4.

TABLE 4 Extension of fringe at a dot area ratio of 50% Standard ImprovedSample treatment treatment L silver chloride emulsion 28 9 silverbromide emulsion 35 10 silver chlorobromide emulsion 23 8 EX A M PLE 5 Afilm was coated with an emulsion consisting of silver chlorobromidecontaining 70 mol silver chloride and gelatin having a silverchlorobromide to gelatin ratio by weight of l:l.3 so as to vary thecoating thick ness thus obtaining three kinds of lith films, A, B and C:

A coated silver amount 51 mg Ag/dm B coated silver amount 42 mg Ag/dm Ccoated silver amount 32 mg Ag/dm Sample A has a coated silver amountnecessary for the ordinary lith film but the coated silver amount ofSamples B and C is not sufficient to give a dot image quality by theknown lith developing method.

When each sample was subjected to dot image exposure and to Improvedtreatment F, a very excellent dot image quality was obtained and theextension of fringe was: Sample A 5p, B 5p. and C 6;!" When it was sub-5 jected to Standard treatment of the prior art, on the other hand, theextension of fringe was: A 20p., B 23p, and C 26 2. Accordingly, samplesof low silver emulsion could be used as a lith film by application ofthe method of this invention.

EXAMPLE 6 When Improved treatment G was used in place of lmprovedtreatment F in Example 5, the extension of fringe was: Sample 3a, B 3a,and C 3p..

EXAMPLE 7 When Improved treatment H was used in place of Improvedtreatment F in Example 5, the extension of fringe was: Sample A 7p, B7p. and C 8p..

EXAMPLE 8 A film base was coated with a silver iodobromide gelatinemulsion (silver iodide 5 mol percent) so as to give a coated silveramount of 40 mg/dm to thus obtain a light-sensitive material for X-rays,which was then subjected to sensitometric exposure and to the followingtreatment:

Prior art method Method of invention development 34 C 60 seconds same asprior art rinse 34 C 30 seconds same as prior art fixing 34 C secondswater washing 34 C 60 seconds bleaching 34 C 40 seconds rinse 34 C 10seconds redevelopment 34 C I50 seconds caustic soda 32 g sodium sulfite83 g I-phenyl-S-pyrazolidone 6.7 g hydroquinone 58 g sodium thiosulfate92 g potassium iodide 03 g water to I000 ml The sample treated by themethod of this invention gave an increase of 50 percent to thesensitivity represented by the reciprocal of exposure quantity giving adensity of above 0.2 fog, as compared with that treated by the prior artmethod. The gamma was increased by 0.3. Moreover, increase of fog couldbe suppressed to 0.03 as compared with 0.09 of the prior art method.

EXAMPLE 9 A superfine grain and high resolving power dry plate of silverchlorobromide was subjected to sensitometric exposure and to thefollowing treatment:

Prior art method Method of invention Development 20 C 5 minutes same asprior art Fixing 20 C 1 minute same as prior art Stopping 20 C 1 minuteWater washing 20 C 2 minutes Bleaching 20 C 20 seconds Rinse 20 C 20seconds Redevelopment 20 C 3 minutes Stopping 20 C I minute Fixing Waterwashing 20 C 1 minute 20 C l minute Relative Gradation sensitivity(Gamma) Prior art method 100 2.5 Bleaching solution l 150 3.6 Bleachingsolution V1 140 4.5 Bleaching solution lll 140 3.4

Although the present invention has been adequately set forth in theforegoing specification and examples included therein, it is readilyapparent that various changes and modifications can be made withoutdeparting from the scope and spirit thereof.

We claim:

I. A method for treating an exposed black-and-white negativephotographic silver halide material to obtain a high contrast silverimage, wherein the chloride content of said silver halide material ispresent in an amount of at least 70 mol percent, which comprises:

a. developing the exposed black-and-white photographic material,

b. bleaching said photographic material without oxi dizing anddissolving the silver in a bleaching solution having a pH of at least 1,and

c. subsequently, negative-developing said photographic material for asecond time with a blackand-white developer.

2. The method of claim 1, wherein the first development step is carriedout with a developer containing hydroquinone and a sodiumsulfite-paraformaldehyde ad duct.

3. The method of claim 2, wherein said developer further contains atleast one member selected from the group consisting of ascorbic acid andsodium sulfite.

4. The method of claim 1, wherein said bleaching solution contains anoxidizing agent and a halide.

5. A method for treating an exposed blackand-white negative photographicmaterial to obtain a high contrast silver image, wherein the chloridecontent of said silver halide material is present in an amount of atleast 70 percent, which comprises the steps of:

a. developing,

b. stopping,

c. bleaching at a pH of at least 1,

d. rinsing,

e. negative-developing,

f. stopping,

g. fixing, and

h. washing.

6. A method for treating an exposed black-and-white negativephotographic material to obtain a high contrast silver image, whereinthe chloride content of said silver halide material is present in anamount of at least mol percent, which comprises the steps of:

a. developing,

b. bleaching at a pH of at least 1,

c. rinsing,

d. negative-developing,

e. stopping,

f. fixing, and

g. washing.

7. A method for treating an exposed black-and-white negativephotographic material to obtain a high contrast silver image, whereinthe chloride content of said silver halide material is present in anamount of at least 70 mol percent, which comprises the steps of:

. developing,

. bleaching at a pH of at least 1,

. rinsing mono-bath negative-developing and fixing, and

. washing.

A method for treating an exposed black-and-white negative photographicmaterial to obtain a high contrast silver image, wherein the chloridecontent of said silver halide material is present in an amount of atleast 70 mol percent, which comprises the steps of:

a. developing,

b. bleaching at a pH of at least 1,

c. mono-bath negative-developing and fixing, and

d. washing.

9. The method of claim 1, wherein said bleaching step is carried outover a period of from 5 to 100 seconds.

10. The method of claim 1, wherein said bleaching step is carried outover a period of from 10 to 30 seconds.

11. The method of claim 1, wherein said second developing step iscarried out over a period of from 10 to 200 seconds. l

12. The method of claim 1, wherein said second developing step iscarried out over a period of from 30 to seconds.

13. The method of claim 1, further comprising at least one stopping,rinsing and washing step conducted after treating steps (a) through (c).I

14. The method of claim 1, further comprising a fixing step, which steptakes place either during or after step (c).

2. The method of claim 1, wherein the first development step is carried out with a develOper containing hydroquinone and a sodium sulfite-paraformaldehyde adduct.
 3. The method of claim 2, wherein said developer further contains at least one member selected from the group consisting of ascorbic acid and sodium sulfite.
 4. The method of claim 1, wherein said bleaching solution contains an oxidizing agent and a halide.
 5. A method for treating an exposed black-and-white negative photographic material to obtain a high contrast silver image, wherein the chloride content of said silver halide material is present in an amount of at least 70 percent, which comprises the steps of: a. developing, b. stopping, c. bleaching at a pH of at least 1, d. rinsing, e. negative-developing, f. stopping, g. fixing, and h. washing.
 6. A method for treating an exposed black-and-white negative photographic material to obtain a high contrast silver image, wherein the chloride content of said silver halide material is present in an amount of at least 70 mol percent, which comprises the steps of: a. developing, b. bleaching at a pH of at least 1, c. rinsing, d. negative-developing, e. stopping, f. fixing, and g. washing.
 7. A method for treating an exposed black-and-white negative photographic material to obtain a high contrast silver image, wherein the chloride content of said silver halide material is present in an amount of at least 70 mol percent, which comprises the steps of: a. developing, b. bleaching at a pH of at least 1, c. rinsing d. mono-bath negative-developing and fixing, and e. washing.
 8. A method for treating an exposed black-and-white negative photographic material to obtain a high contrast silver image, wherein the chloride content of said silver halide material is present in an amount of at least 70 mol percent, which comprises the steps of: a. developing, b. bleaching at a pH of at least 1, c. mono-bath negative-developing and fixing, and d. washing.
 9. The method of claim 1, wherein said bleaching step is carried out over a period of from 5 to 100 seconds.
 10. The method of claim 1, wherein said bleaching step is carried out over a period of from 10 to 30 seconds.
 11. The method of claim 1, wherein said second developing step is carried out over a period of from 10 to 200 seconds.
 12. The method of claim 1, wherein said second developing step is carried out over a period of from 30 to 80 seconds.
 13. The method of claim 1, further comprising at least one stopping, rinsing and washing step conducted after treating steps (a) through (c).
 14. The method of claim 1, further comprising a fixing step, which step takes place either during or after step (c). 